Thermoelastic properties of cross-bridges in skinned skeletal muscle fibers of the frog under a condition of rigor

Thermoelastic properties of cross-bridges were measured by application of small sinusoidal length perfurbations and submillisecond Joulean temperature jump to chemically skinned muscle fibre removed from rigor solution. The thermal expansion coefficient of fibres was 4.2 +/- 1.0 X 10(-5) K-1. We have observed neither rubber-like stiffness increase, nor tension increase and stiffness decrease (which are expected if alpha-coil melting occurs) after temperature jump.